Computing machines



July 29, 1958 w. L. TANCRED COMPUTING MACHINES l0 Sheets-Sheet 1Original Filed Aug. 18, 1949 INVENTOR \A/lLuAm L. TANCRED ow MMWWQMATToRNEYS July 29, 1958 w. L. TANCRED COMPUTING MACHINES Original FildAug. 18, 1949 l0.Sheets-Sheet 2 INVENTOR WILLIAM L. TANCRED WM 600, MYWMATTO'RN EYS 10 Sheets-Sheet 3 INVENTOR \A/DLLIAM LTANCRED M MWJWWATTORNEYS W. L. TANCRED COMPUTING MACHINES EEUEEH 553555 m mmmm July 29,1958 Original Filed Aug. 18, 1949 July 29, 1958 w. L. TANCRED COMPUTINGMACHINES l0 Sheets-Sheet 4 Original Filed Aug. 18, 1949 INVENTOR WILLIAML. TANCRED 0224, M M WWW ATTORNEYS July 29, 1958' w. L. TANCREDCOMPUTING MACHINES 1o Sheets-Sheet 5 Original Fil ed Aug. 18, 1949 \mmwm R n O .m m n m L m m L m @M Q Q 5 ATTORNEYS July 29, 1958 w. L.TANCRED COMPUTING MACHINES 1O Sheets-Sheet Original Filed Aug. 18, 1949INVENTOR WILLIAM L. TANcRED ATTORNEYS W. L. TANCRED COMPUTING MACHINESJuly 29, 1958 10 Sheets-Sheet 7 Original Filed Aug. 18, 1949 INVENTORSWILLIAM 'L. TANCRED y m, M, 291% wowam ATTOR NE Yb July 29, 1958 w. L.TANCRED COMPUTING MACHINES l0 Sheets-Sheet 8 Original Filed Aug. 18,1949 INVENTOR \A/ILLMM L. TANCRED Wm 84-6 Mwwm ATTORNEYS w. L. TANCREDCOMPUTING MACHINES July 29, 1958 10 Sheets-Sheet 9 Original File d Aug.18, 1949 INVENTOR \A/uum L. TANCRED ATTORNEYS July 29, 1958 w. 1..TANCRED COMPUTING MACHINES 10 Sheets-Sheet 10 Original Filed Aug. 18,1949 R o T N V m \A/ILLIAML TANQRED Wm, M P 1 434 ATTORNEYS nited Statesatent Ofiice COMPUTING MACHINES William L. Tancred, Wethersfield, Conn.,assignor, by mesne assignments, to John H. Reid, Hartford, Conn., andSidney W. Felton, Salem, Mass, as trustees Original application August18, 1949, Serial No. 110,980,

new Patent No. 2,753,111, dated July 3, 1956. Divided and thisapplication May 28, 1956, Serial No. 587,750

1 Claim. (Cl. 235-60) This invention is a division of that described inmy U. S. Patent No. 2,753,111, which was issued on my copendingapplication Serial No. 110,980, filed August 18, 1949.

This invention relates to computing machines, and more particularly tomachines for performing addition and subtraction.

An object is to provide means for limiting the speed of motion of partsso that they will not over-travel or produce inertia shocks and which atthe same time produce a small vibration which tends to prevent stickingof movable parts.

Further objects and advantages will appear from a description of anembodiment of the invention shown in the accompanying drawings in which-Figures 1 and 2 are top plan and right side elevational views,respectively, of a machine embodying the invention.

Figure 3 is a vertical sectional View on line 3-3 of Figure 1.

Figures 4 and 5 are detail sectional views on lines 4-4 and 5-5,respectively, of Figure 3.

Figures 6 and 8 are detail sectional views on lines 6-6 and 8-8,respectively, of Figure 5, Figure 8 showing the totalizer engaging partsin adding relation.

Figure 7 is a fragmentary exploded perspective View of certain parts ofthe totalizer engaging mechanism.

Figures 9 and 10 are views somewhat similar to Figure 8, but showing thetotalizer engaging parts in subtracting and clearing relations,respectively.

Figures 11 and 12 are views similar to Figure 10, but with parts omittedor broken away, the parts shown being in successive positions after thepositions shown in Figure 10 during a clearing operation.

Figure 13 is a longitudinal sectional view on lines 13-13 of Figure 5,the parts being shown in neutral or starting position.

Figure 14 is a fragmentary view similar to a portion of Figure 13 butshowing the actuating parts at the start of an adding operation on atotalizing wheel.

Figure 15 is a detail sectional view on line 15-15 of Figure 5, theactuating parts being shown at the end of an adding action on atotalizer wheel with a carryover.

Figure 16 is a fragmentary view similar to a portion of Figure 15, butwith the actuating parts in neutral positions.

Figure 17 is a detail sectional view on line 17-17 of Figure 15 showingthree totalizer wheels with certain of their actuating parts, one of thetotalizing wheels being shown in section.

Figure 18 is a detail sectional view on line 18-18 of Figure 17.

Figure 19 is a fragmentary sectional view on line 19-19 of Figure 3.

Figure 20 is a fragmentary sectional view on line 211-20 of Figure 19.

Figure 21 is a detail sectional view on line 21-21 of Figure 3.

Figure 22 is a fragmentary view to a larger scale partly in elevationand partly in section of one of the number keys and its spring.

Figure 23 is a fragmentary sectional view with parts broken away online23-23 of Figure 3, the selector stop carriage being shown at thestarting of an adding or subtracting operation.

Figure 24 is a view similar to a portion of Figure 23, but showing theselector stop carriage at its final limit of motion as when a series ofactuating number keys equal in number to the totalizing wheels have beendepressed.

Figure 25 is a detail sectional view on line 25-25 of Figure 23.

Figure 26 is a fragmentary view partly in front end elevation and partlybroken away and in section and showing mechanism also appearing inFigure 25.

Figure 27 is a perspective view of the undercarriage and spring bar andone of the totalizer rack pilot bars.

Figure 28 is a fragmentary perspective view of a portion of the selectorstop carriage and related part showing the safety catch for thecarriage.

Figure 29 is a fragmentary perspective view showing the releaseretaining mechanism eifective in the clear adjustment.

Figure 30 is a view similar to a portion of Figure 13, but showing amodified carry-over mechanism.

Figure 31 is a view similar to Figure 15, but showing the same mechanismas Figure 30.

Figure 32 is a view similar to Figure 17, but showing the carry-overmechanism of Figures 30 and 31.

Figure 33 is a fragmentary exploded perspective view of certain of theparts in the modified carryover mechanism of Figures 30, to 32,inclusive.

Number selecting mechanism Projecting through the cover member 1 of themachine casing 2 are ten selector keys 3, 4, 5, 6, 7, 8, 9, 10 11 and 12which correspond to the digits zero to 9, inclusive (Figures 1 and 2).Each of these keys has a shank 15 which extends slidably through thecasing 1 and through slots in a transverse partition 16 (Figure 3). Eachof these shanks beneath the cover 1 is provided with a lateral arm 17which extends over one or the other of a pair of hinged equalizer plates18. These plates 18 are provided with ears 19 along their remote edgeswhich extend through slots in flanges 20 upstanding from the transversepartitions 16. These plates 18 are cut away centrally as at 21 and atopposite sides of the cut away portion they overlap in sliding hingeformation at 22 (Figs. 19 and 20).

The extremities of all of the arms 17 are brought into an alined seriesas at 25, except that extending from the key 12 representing the digit9. The extremity of this arm 17a terminates above one of the plates 18.The mating edges of the plates 18 are normally held elevated against theunder edges of the various arms 17 as by suitable leaf springs 28, thelower ends of which are secured to the top face of the partition 16 asby rivets 29 (see Figure 19).

Each of the keys may be held normally elevated as by a leaf spring 30supported at one end of the partition 16 and at the other end engagingin a notch 31 in the lower portion of the key shank 15. These springs30, as shown in Figure 22, have normally straight intermediate portionswhich buckle when the corresponding key is depressed substantially halfWay down, giving a distinctive feel to the operator so that he may besure that each is depressed a full stroke.

The extremities of the arms 17 in the alined series 25 are positionedabove a plurality of series of selector stops 35, there being nine suchstops in each of a plurality of rows, the number of rows being equal tothe number of digits which it is within the capacity of the machine tototal. As shown there are nine such rows, and these selector stops aremounted vertically in a carriage 40 mounted for motion transverse of themachine. As shown best in Figures 3, 5, 13, 14 and 19, this carriage issupported for lateral sliding motion on a rod 41 which ex.- tends acrossthe machine and on the lower forwardly turned extremity 42 of alaterally extending frame member 43 depending from the frame member 16Each of the selector stops 35 is vertically movable in the carriagebetween either of two positions in each of which it may be yieldinglyretained as by the engagement in one or the other of a pair of notches45 in its side face of a V extremity of a looped leaf spring 46. Asshown, for example, in Figure 21, one of these selector stops at theleft hand end of the row has been depressed so that the spring 46engages in the upper notch 45, while the remainder of the selector stopsare shown in raised position with the corresponding leaf spring in thelower notch 45.

Beneath the carriage 40 and toward the right hand side of the machinethere is positioned a cam plate 47 (Figure 21) having at its left edge adown-turned portion 48 so that when the carriage 40 is moved to itsright hand position, any of the selector stops 35 which may have beendepressed are cammed up to their upper positions and ride upon the topface of the plate 47. As the carriage is moved toward the left, theseveral rows of selector stops are brought sequentially beneath theseries of extremities 25 of the selector keys so that whenever one ofthese selector keys is depressed, the corresponding selector stop in itsseries is also depressed. After each actuation of a number key todepress a selector stop the carriage 40 moves to present the next row ofselector stops beneath the series of actuator extremities. The mechanismby which this is accomplished will now be explained.

Referring to Figures and 23 to 25, it will be noted that the carriage 40has fixed thereto one end of a flexible ribbon 50, the opposite end ofwhich engages more or less about the periphery of a segment 51 which isfixed to a vertical pinion shaft 52 which has at its lower end a pinion53. With this pinion meshes a rack bar 54 carried by a slide plate 55which is normally pulled forwardly as by a spring 56 secured atone endto the rear down-turned extremity 57 of the slide plate 54, and at itsother end to the extremity 570 of a lever 58 which extends across themachine and has a pivotal end portion 581 fulcrumed in an opening 59 inthe left hand wall of the casing 2. A

roller 580 carried by the lever 58 and bearing against the inner face ofthe partition 217 retains the lever 58 in position. The slide plate 54has a longitudinal slot 60 through which the shaft 52 passes and aparallel slot 61 through the segment 51 against which it isheld as by aroller 65 carried by a fixed frame member 66 and spaced sufiicientlyfrom the periphery of the segment 51 topermit the passage of the ribbon50 between them. As a result of the described arrangement, the energystored in the ribbon spring 50 is applied with a positive gradient as itis unwound, i. e., its force is increased as the carriage 40 is advancedto the left--while the energy stored in the coil or tension spring 56 isapplied with a negative gradient, its force being decreased as thecarriage is advanced to the left. The combination of the two springs,arranged as described, results in their stored energy being applied witha flat gradient, i. e., the carriage 40 advances by an equalized forceto the left. The force at the beginning of the travel is thus the same.as at the end of travel. Along itsforward upper edge the carriage 40 isprovided with a forwardly extended flange member 70 which is formed onits edge with a plurality of notches 71 between forwardly extendingteeth 72, and means are provided cooperating with these teeth andnotches for permitting the carriage to be moved by the action of thespring 56 from the position shown in Figure 23 toward that shown inFigure 24 by a series of steps, each suflicient to remove one row ofselector stops out from beneath the extremities 25 of the selector keysand to bring the next row of selector stops into the same position, andthis action takes place each time a number key is depressed. Themechanism for accomplishing this is shown best in Figures 19 and 20.

Referring to these figures, pivoted to :1 lug 75 on a fixed frame member76 is one end of a dog 77 having a downwardly extended hook portion 78at its opposite end. This dog 77 intermediate to its ends is turned tothe left, or upwardly as shown in Figure 20, and overlies a second dog79 which is pivoted to the dog 77 at 80. This dog 79 has at its innerend an upturned hook member 81. When the equalizer plate 18 is depressedby depression of any of the number keys, the dog 77 and the dog 79, areboth depressed, the hook portion 81 is depressed from one of the notches71, while the hook portion 78 comes down in front of one of the teeth72. Thus the carriage is released for a step motion toward the partialleft as the hook 81 is depressed and the carriage steps over until oneof the teeth 72 contacts with the hook 78. On subsequent lifting of theequalizer plate 18, the dog 71 is lifted by the action of a leaf spring85 which bears on its under face and is threaded through a pair of holes86 and 87 in the frame member 76. The hook 81 then comes into the nextnotch 71 and further lifting of the dog 79 lifts the fulcrum 80 until aroll 88 thereon is stopped by engagement with a positive stop member 89.The hook 78 is then out of contact with the carriage and so remainsuntil it is depressed by a subsequent depression of any one of thenumber keys. With this arrangement, each time the operator depresses anumber key, the carriage moves over by one step, the number of stepscorresponding to the number of digits in the number which is to be addedor subtracted, at each actuation of a number key there being acorrespondingly positioned selector stop in the corresponding row ofselector stops depressed. For example, as shown in Figures 13 and 14,the No. 4 stop is depressed in the particular row in position where thecarriage was when the number key was depressed. At each actuation of thetotalizing mechanism the carriage is moved back to its extreme righthand or starting position by means which will later appear.

Means are also provided by which the carriage is prevented from beingmoved to its initial position accidentally as by the machine beingdropped on its edge or other wise receiving rough handling. This meanscomprises a third dog 95, shown best in Figures 19 and 28, this doghaving a downwardly projecting point 96 adapted to project into one ofthe notches 71 at the right hand face of a tooth 72. This dog 95, asbest shown in Figure 28, comprises an angle member, one arm 97 of whichis provided with an upstanding lug- 98 fulcrumed on a shaft 99 mountedat its ends in a bearing lug 100, and in a flange 101 upstanding fromthe cross frame member 16. Also rockable on the shaft 99 is a U-shapedportion 102 of an arm 103 which has an upstanding and forwardly turnedend portion 104 against which one of the side arms 105 of the totalizingactuating mechanism engages when this actuating mechanism is in itsneutral position. A spring 106 has one end engaging the upper edge ofthe dog 95, its intermediate portion is wound around the shaft 99, andits opposite end portion engages the side of a lug 108 upstanding fromone arm of the U-shaped member 102. The spring 106, when the arm 103 isin the position shown in Figure 28, is tensioned to hold the dog in itsdownward locking position back of one of the teeth 72. A spring 108 heldat one end at a fixed point 109 of the frame member 16 and at its otherend secured to the U-shaped portion 102 at acts, whenever the handle bar105 is rocked away from the member 103, to rock this member 103 in adirection to relieve the pressure of the spring 106 in downwarddirection and lifts the dog 95 out of position to'obstruct the returnmotion of the carriage.

T otalizer As shown, the totalizer comprises a series of digit wheelsjournaled on a shaft 121 which extends across the machine, each of thesewheels 120, as shown, carrymg two complete sets of digits from 0 to 9 onits periphery, one digit at a time of the several wheels being visiblethrough a window 125 in the top of the casing. As shown, each of thewheels comprises a pair of disks 126 and 127 secured to the hub portions128 and 129 of a pinion 130. These disks 126 and 127 are provided withannular stiifening ribs 131 and one of the disks, as at 126, has a rimportion 132 which carries the digit indications. At diametricallyopposite points, the disk 12'? has outwardly projecting ears 135 and oneof these cars is in position to act on other mechanism when the disk isbeing turned between positions where a 0 and a 9 thereon are movingbeneath the window. These disks are in number equal to the number ofdigits which it is within the capacity of the machine to register, ninesuch disks being shown, although more or less might be employed asdesired.

Except when a wheel is to be turned, it is held locked against turning,and locking means for each wheel consists of a finger carried by aU-shaped member 141 which extends across the series of totalizer wheels,the end walls of which are slotted to slidably engage guides 142 coaxialwith the totalizer shaft 121. The fingers 140 are provided with teeth143 adapted to engage between the teeth of the corresponding pinion 130.The U-shaped member 141 is supported by a hanger 144 carried by a shaft145. By rocking this shaft from the position shown in Figure 13 to thatshown in Figure 14, the fingers 140 may be retracted from theirrespective pinions, thus unlocking the totalizer wheels for turningmotion.

T otalizer actuating mechanism The totalizer mechanism is actuated bythe rocking of a handle bar which extends across the machine toward itsfront end and is carried at opposite ends by a pair of arms 105. Thesearms extend through slots in the top wall of the casing, and towardtheir lower ends these arms 105 are fulcrumed on a transverselyextending shaft 156. Beneath the top frame member the arms 105 arecross-connected by a transverse member 157 which may be integral withthese arms. The lower ends of the arms 105 beneath the fulcrum shaft 156are pivoted as at 158 to the forward ends of a pair of links 159 towhich are attached the forward extremities of a pair of rods 160 whichextend slidably through end flanges 161 and 162 of U-shaped links 163,withdrawal from which is prevented by suitable means such as lock nuts.A spring 164 surrounds each of the rods 160 and bears at its forward endagainst an in-turned end flange 165 of the link 159 and at its other endagainst the flange 161. This provides a yielding connection between thelower ends of the arms 105 and the members 163. The members 163, inturn, are connected by pivot and slot connections at 167 to theintermediate portions of a pair of arms 170, pivoted at their upper endson trunnions 1'71 and pivotally connected at their lower ends as at 172to a pair of links 173, the rear ends of which are, in turn, pivoted at174 to side members 175 (see particularly Figure 27) of anunder-carriage. These side members 175 are supported at their rear endson a transverse rod 176 which passes through slots 177 therethrough.These side members 175 are connected together as by a transverse plate178 which may be integral therewith and which has a forward centralextension 179 which may be provided along one edge with a rack portion180. This rack portion 180, as shown best in Figures 23 and 24, may meshwith a pinion 181 on a shaft 182 which also carries a wheel 183 having aserrated periphery and is held in such mesh by an idler 1630 with whichthe opposite edge of the extension 1'79 engages. This wheel 183 is aportion of a damping mechanism, which may be employed, if desired, tolimit the speed of actuation of the parts and thus avoid undesirableinertia forces. Cooperating wi h the serrations on the periphery of thewheel 183 are a pair of pins 184 carried by an oscillator bar 185fulcrumed at 186. This oscillator bar may be of some weight. Turning ofthe wheel 183 causes its serrations to engage with the pins 184,imparting a rapid oscillation to the bar 185 which produces the desiredspeed limiting action due to inertia of the bar 185. It also imparts avibration which acts on the various portions of the machine to avoidsticking of the parts under friction of rest, resulting in a sensitivityof action which causes prompt response of the various mechanisms toactuating pressure. The wheel 183 and the bar 185 are preferably ofmaterial such as hard fibre or resin composition to avoid noisyoperation. The forward end of the member 179 is narrowed, and providedin its narrow portion with a pair of upstanding flanges and 191.Adjacent to its widened rear portion it has upstanding therefrom aroller journaled on a post 196. The lever 58 hereinbefore mentioned inconnection with the carriage mechanism bears against the rear edge ofthe cam roll 195 as shown best in Figure 23 for a purpose which willlater appear.

The side members 175 of the under-carriage are provided with a pair ofopposed longitudinal slots 200 within which is slidably mounted the endportions of a spring bar 201 and arranged along this spring bar andperpendicular thereto are a series of totalizer pilot bars 202, therebeing one of these pilot bars for each totalizing wheel, Figure 27showing but one of these bars in position. They are all alike, however,so that a description of the mounting of the one shown in Figure 27 willsufiice for each. Each is provided with a longitudinal slot 203 throughwhich the spring bar 201 passes, this slot 203 being of increased widthtoward its rear end, as at 204, where it is slidably guided on the crossrod 176 shown in Figures 8 to 16, inclusive. The under side of itsforward portion is cut away as at 205 and houses therein a coil spring206, the forward end of which is engaged with the bar 202 through a hole207 therethrough, and the rear end of which is engaged in a hole 208through the spring bar 201. Each of the bars 202 is therefore connectedto the spring bar 201 yieldingly and the spring bar is connected througha lost motion of the slots 200 with the under-carriage. The forward endof each bar 202 is provided with a longitudinal slot 210 within whichrides the pivot shaft 156, opposite ends of each bar 202 thus beingsupported for axial sliding motion on the pivot shaft 156 and thetransverse bar 176.

With this construction it will be noted that when the handle bar 150 isswung forwardly and downwardly, as permitted by arcuate slots 215 in apair of inner longitudinal partition members 216 and 217, through whichthe connecting member 157 of the arms 105 passes, the bars 159 are movedrearwardly and through the springs 164- and the members 163, the levers170 and the links 173, the under-carriage is given a rearward motion.The speed of carriage motion is regulated by the speed of rotation ofthe notched wheel 183, which, however, does not interfere with the rateof motion of the handle bar 150, any difference in speed being taken upin compression of the springs 164.

Through the springs 206, a pressure tending to move each of the bars 202rearwardly is also produced, but some of these bars, depending upon thelateral position of the selector stop carriage, may not be able topartake of such motion. This is for the reason that they may be heldback by hooks 220 (Figures 3, 13 and 14), one for each of the bars 202being fulcrumed on a shaft 221 held in supporting lugs 222 and 223 onthe inner faces of the partitions 216 and 217, as shown best in Figure4. The rear ends of the hooks 220 may be held in inoperative positionsby a forwardly directed flange 224 on the lower forward edge of theselector stop carriage as is shown in Figure 14-. This flange 224 holdsthose hooks inoperative which are associated with the pilot bars of thedenominational orders which were employed in setting up a particularnumber in the machine. All the other hooks, at the time of actuation ofthe handle bar 150, will be depressed at the time of such actuation,bringing a shoulder 225 on each beyond a stop flange 226 on thecorresponding pilot bar 202, thus preventing the backward motion of thecorresponding bar 202 when the handle 150 is pulled downwardly andforwardly.

Those bars 202 which are not so locked will be pulled rearwardly by therearward motion of the undercarriage until a second stop element 227thereon engages against that particular selector stop of the selectorstop carriage which was deprmsed by the depression of the correspondingnumber key. For example, as shown in Figures 13 and 14, the selectorstop corresponding to the four-digit key is depressed, so that thecorresponding stop lug 227 of the corresponding pilot bar 202 will moverearwardly into contact and be stopped thereby. It will be noted that onthe rear edge of the selector stop carriage there is a downwardlydepending flange 230 which provides a stop corresponding to thedepression of the 9-digit key. This is the extreme limit of motion ofany of the bars 202 so that it is not necessary to provide a movableselector stop for this digit key. Consequently this digit key, as shownbest in Figure 20, extends only into contact with one of the equalizerplates 18 as at 17a.

Means are provided by which the hooks 220 are lifted above the flange224 when the handle bar 150 is in normal position, so that they will notinterfere with the lateral motion of the selector stop carriage. Thislifting is done by the following means. On the inside face of each ofthe partitions 216 and 217 are pivoted a pair of dogs 235, as on thepivots 236. Each of these dogs has a shoulder 237 which is contacted bythe crossbar 157 of the handle mechanism when this handle mechanism isin its forward position, shown for example, in Figure 13. Bridgingacross from one to the other of these dogs 235 is a somewhatchannel-shaped member 238 which has a curved marginal flange 239 whichrides upon a cam surface 240 on a tail portion 241 of each of the hooks220. This cam surface 240 is held into contact with the portion 233 asby a spring 243 for each of the hooks 220, this spring being connectedat one end to the hook as at 244 and at its other end to the oppositeedge flange 242 of the member 238. The cam surface 240 is so shaped thatwhen the handle bar 150 is in its rearward, normal, position and theportion 239 engages the upper portion of the came face 240, the tailportions 241 are pressed forwardly and downwardly, lifting the rearwardends of the hooks into the position shown in Figures 3 and 13. When thehandle bar member is moved downwardly, the dogs 235 tilt as shown inFigure 14, allowing those hooks which are not positioned above thecarriage flange 224 to drop down until their shoulders 225 engagerearwardly of the lugs 226 of the corresponding actuator bars 292. Onlythose pilot bars 202 which are held free by the hooks 220 riding on thecarriage flange 224 are then permitted a backward movement in responseto the downward swing of the handle 150, and those pilot bars 202 whichare permitted such a motion are permitted this motion only to the extentdetermined by the particular selector stop which was depressed by theaction of a number key, or in case the No. 9 key was depressed by thecarriage flange 230. This motion of the pilot bars is caused to actuatethe corresponding totalizing wheels selectively to rotate these wheelsin adding or subtracting direction, or to bring all. the wheels. to 0position to clear the machine for the commencement of the next addingoperation.

Each of the bars 202 is arranged to actuate, under suitable controlledconditions, a totalizer bar 250 which is mounted directly beside itspilot bar 202. It is mounted for sliding motion on the shaft 221 whichpasses through a guide slot 251 through the forward end portion of thebar 250 and its rear end, has a similar slot 252 through which extends asecond guide bar 253. This guide bar 253, however, is movable up anddown within vertical guide slots 2531 in the wall members 216 and 217,so as to present either an upper downwardly facing rack bar portion 255,or a lower upwardly facing rack bar portion 256 at its rear end intoengagement with the corresponding pinion of a totalizer wheel, or to bein an intermediate position where both of these rack bars are out ofengagement with the pinion. The upper rack bar is shown in engagementwith the pinion in Figure 9 and the lower rack bar is shown in suchengagement in Figures 8, 14 and 15, while the rack bar is shown in theintermediate position with neither rack bar in engagement with. thepinion in Figures 13 and 16. It will thus be noted that the rack barsare spaced a distance slightly greater than the maximum diameter of thepinion.

In order to adjust the guide bar 253 between its three positions ofelevation, its opposite ends are carried by a pair of cams 260, one ofwhich is shown best in Figure 7. Each cam 260 is supported between apair of fixed abutment pins 261, 262 diametrically oppositely disposedto the guide bar 253 and supported by the frame members 216' and 217.Each of the cams 260 has an external cam face including a high arcuateportion 265 and a low arcuate portion 266 which are arrangeddiametrically opposite to each other. Between these high and-low arcuateportions are portions 267 of intermediate height. The pins 262 are inline with the slots 2531 and are so spaced apart that when one engagesthe high arcuate portion of the cam, the other engages the low arcuate,portion and the guide bar 253 is held in either its upper or lowerextreme positions.

Means are provided by which the cams 260 are rocked angularly about theaxis of the guide bar 253, this rocking motion causing the guide bar 253to be moved vertically in its guide slots so as to take either itsextreme upper position, its extreme lower position, or an intermediateposition. In the upper position the lower rack bars are moved up intoengagement with their mating pinions. In the intermediate position bothrack bars are out of engagement with their pinions, and in the lowerposition the upper rack bars are in engagement with the pinions.

The means by which the cams are rocked to take these various positionscomprise a trace 270, shown detached in Figure 7 and positioned to theright of the partition 217. Its rearward end portion is pivoted as on apivot pin 271 which passes through a hole 272 in the trace, and it alsohas a longitudinal slot 273 therein through which passes a pin 274projecting from the lower end of an L-shaped member 275 which is alsofulcrumed at its perforation 276 on the pivot pin 271 (see also Figures3 and 8 to 12 inclusive). At the upper end of this L-shaped member thereis attached one end of a coil spring 277, the opposite end of which isattached to a fixed pivot post 278. This spring tends to hold the upperportion of the L-shaped member 275 rocked against a stop lug 279projecting from the forward edge of a lever 280, the lower end of whichis also pivoted on the pivot 271 (see Fig. 10) on frame 217. This lever280 projects upwardly through a slot 289 in the top of the casing andhas an actuating knob 290 at its upper end. The slot 289 is normallycovered by a sliding plate 291 which moves with the lever 280. The lever280 has three positions, its forward position shown in Figure in whichthe stop lug 279 is out of contact with the forward edge of the L-shapedmember 275, an intermediate position shown in Figures 3 and 7 where theL-shaped member 275 is in contact with the stop lug 278, and a thirdrearward position where the stop lug 275 is still in contact with themember 275 but in which the memher 275 is rocked rearwardly with its pin274 in its upper position, rocking the trace upwardly into the positionshown in Figure 9. The L shaped member 275 has but two angularpositions, in one of which the rear end of the trace 270 is lifted asshown in Figure 9; the other in which the rear end of the trace islowered as shown in Figures 3, 8 and 10. Addition When the knob 290 isin its intermediate position, the parts are positioned to causeoperation of the machine to add, and in this position of the parts, theL-shaped member 275 is so disposed as to lower the forward end of thetrace. The operator presses the number keys corresponding to the digitsin the number which is to be added, starting from the left hand digit,and when this has been completed, he rocks the handle bar 150 downwardlyand then allows it to return to its former position. The rocking of thehandle bar 150 downwardly through the means previously described causesthe under-carriage to move rearwardly. After a small lost motion of theunder-carriage until it contacts the spring bar 201, the spring barmoves forwardly with the carriage, and through the springs 206 moves allof the pilot bars, which have been held unlocked by the selector stopcarriage flange 224 holding the locking hooks elevated, as far aspermitted by the particular selector stops which have been depressed inaccordance with the particular number keys which have been depressed.This backward motion of each of the pilot bars 202 which have beenreleased, acts through a pin 295 on the corresponding totalizer bar 250which contacts a shoulder 2990 on the pilot bars to move the totalizerbar rearwardly. At this time the guide bar 253 is in its intermediateposition so that the totalizer bars move rearwardly out of contact withthe pinions of the totalizer wheels. It will be noted that theundercarriage moves through its complete length of stroke at each fullactuation of the handle bar 150, but the length of stroke of each of thepilot bars 202 and its totalizer bar 250 is dependent upon theparticular selective stop which is contacted by the lug on the bar 202,thus limiting the lengths of stroke of the rack bars to distancescorresponding to the particular number of the number key which controlsit. The backward motion of the under-carriage continues until theforward end of the slot 177 engages the cross bar 176, whereupon thiscross bar 176 is carried with it for the remainder of its stroke. Thiscross bar 176 at its right hand end engages in a perforation 300 in ahanger 301, shown detached in Figure 7, and which is provided withspaced slots 302 and 303 adjacent to its ends through which pass fixedpins 304 and 305 projecting inwardly from the side wall 217 so that thishanger is permitted a limited horizontal motion. It carries an inwardlyprojecting pivot pin 271 which engages in the pivot opening 272 of thetrace 270 so that this trace is given a rearward motion during the lastportion of the rearward motion of the under-carriage. The forward end ofthe trace is provided with a pair of oppositely disposed arcuate slots311 and 312 within which are adapted to ride spaced pins 313 and 314,respectively, projecting outwardly from the right hand cam 260.

When the trace is in its lowered position, as in the adding positionassumed, the pin 314 is in the slot 312 and as the trace is pulledrearwardly the cam 260 is rocked from the position shown in Figure 3 tothe position shown in Figure 8. This rocks the cams 260counterclockwise, causing the cams, which ride between the fixedelements 261 and 262, and the bar 253 to be lifted. This lifts the rearends of the totalizer bars,

bringing the lower rack bars of each into mesh with the totalizer gearsin the position shown in Figure 8. It will be noted, however, that allthe rack bars which have been moved are then in rearward, differential,positions which have been determined by the particular number keyspreviously depressed for controlling the particular totalizer bars, sothat the distances inwardly from the rear ends of the rack bars wherethey engage their pinions is dependent upon the particular number keywhich controls each. The rearward motion of the hanger 301, through apivoted link connection 320 with the totalizer locking shaft 145, causesthe rockings of this shaft in a direction to withdraw all of the lockingfingers from locking engagement with the totalizer wheels, thus freeing.them for rotation. Releasing of the handle bar allows a pair of springs325 attached at their rear ends to the forward ends of theunder-carriage side bars 175, as through the perforations 326 andattached at their forward ends to fixed points 327 of the machine frame,to retract the under-carriage. The spring bar 201 being pulled back bythe under-carriage, engages the forward ends of the slots 233 in each ofthe pilot bars which have been moved forwardly to any extent andretracts them all to starting position. Through the springs 296 whichengage the pins 2% on the totalizer bars and pins 329 on the pilot bars,the rack bars which were moved forwardly when the handle 150 wasdepressed are pulled back to their starting positions, turning thecorresponding totalizer pinions and totalizer wheels, by amountscorresponding to the controlling number keys which were initiallydepressed. The return motion of the under-carriage also causes a similarreturn motion of the hanger 301, together with the corresponding motionof the trace, which acts upon the lower pin 314 to rock the camsclockwise to their starting position and lower the cross bar 253 tostarting position. The return of the hangers also returns the lockingfingers 140 to locking positions, retaining the totalizer wheels in thepositions to which they have been moved by the action of the rack bars.This return motion of the handle 150 also acts to return the stepselector carriage to its right hand limit of motion and to return theselector stops previously depressed to initial position' The return ofthe carriage will be described later.

T otalizer carry-over It will be evident that whenever a totalizer wheelis turned to pass from the 9 indication opposite the sight window to a0, it is necessary to turn the next adjacent totalizer wheel to the leftby one numeral. Means for effecting this will now be described.

As previously noted, each of the totalizer wheels has a pair ofoutwardly projected diametrically opposed ears 135. As the numberindication visible on a wheel is passing between the 9 and 0, one ofthese ears 135 engages and passes across a follower projection 330 on atrigger arm 331 pivoted on a cross shaft 332 (see Figures 13 to 16,inclusive). Each arm 331 has an upwardly extending notch 333 thereinwhich engages over a pin 334 on a hook lever 335 fulcrumed on the bar253. The hooked extremity 336 of this hook is adapted to engageforwardly of a lug 337 projecting from the side face of the nexttotalizer bar 250 to the left of the totalizer wheel whose car 135contacts the cam follower lug 330, such engagement normally defining theforward or starting limit of motion for each totalizer bar, there beingone such hook for each totalizer bar. The engagement of the car 135 onthis cam follower projection swings the corresponding arm 331 from thefull line position shown in Figures 13 and 14 to the position shown inFigures 15 and 16 which releases the hook 336 from the lug 337 andpermits the spring 296 of the totalizer bar to pull the totalizer barforwardly until its pin 295 strikes the shoulder 2990 of its pilot barwhich is just sufficient to turn the corresponding totalizer wheel byone digit indication. The lower end portion of each arm 331 is providedwith a latch pin 340 which rides on the upper face of a leaf spring 341having a central hump 342. This spring acts as a latch to yieldinglyretain the arm 331 in either of the angular positions into which it maybe put, both being shown in full and dotted line in Figure 16. The lowerend of each arm 331 also projects downwardly as at 342 into the path ofmotion of a finger 343 carried by the spring bar 201.

On the next downward motion of the handle bar 150 the rearward motion ofthe pilot bar immediately starts the. rearward motion :of the releasedtotalizer bar without .the starting lost motion present when the forwardmotion of the totalizer bar was stopped in normal position by its hook336. The arm 330 is also returned to its former position lifting thehook 336 into operative position when the finger 343 of the spring barengages and moves the lower end of the arm 330 rearwardly.

Totalizer carry-over modification A totalizer carry-over mechanism ofmodified construction is illustrated in Figures 30 to 33, inclusive. Inthis modification the trigger arm 331a is substituted for the triggerarm 331 shown in Figures 13 to 16, inclusive. The trigger arm 331a isfulcrumed on the shaft 332 and is provided with an edge 451 whichnormally engages against a laterally extending lug 452 on a pawl 453pivoted at 454 to a cmrier 450. This carrier 450 is supported on thevertically movable bar 253 and has a slot 455 in its upper edge slidablyguided on the shaft 332. The normal position of the parts is shown inFigure 30. The pawl 453 is normally held by a spring 456 attached atopposite ends in a hole 457 in the carrier 450 and a hole 458 in thepawl in angular position to cause the edge 451 of the trigger lever toengage the lug 452 of the pawl and hold the pawl with its latch edge 460in position for the edge 461 of the next totalizer bar 250a to. the leftof the controlling lever 33101 to impinge thereon when the totalizerbars are returned forwardly. The totalizer 250a is not provided with anylug 337 since this is not needed with the construction herein shown.Whenever the lug 330a of the trigger lever 33111 is struck by an ear 135of its totalizer wheel, throwing the trigger lever 331a to its left handposition shown in Figure 31, the portion 451 of the trigger lever rocksupwardly and tilts the pawl 453 counterclockwise, removing its edge 460from obstructing position for the edge 461 of the totalizer bar next tothe left, this permitting this bar to retract by one further totalizingwheel indication, and effecting the desired carry-over. Backward motionof the under carriage in the next operation of the machine returns theseparts to normal positions, as described in connection with Figures 13 to16, inclusive. This modified mechanism has the advantage over themechanism shown in Figures 13 to 16, inclusive, in that it is liftedwhere it is more accessible for inspection and repair when the cover ofthe machine is removed.

Subtraction When it is desired to subtract it is first necessary toposition the totalizer wheels in accordance with the minuend, the numberbeing set on the keyboard starting from the left hand digit of thisnumber. The handle 150 is then depressed and allowed to lift again, thusshowing the desired minuend beneath the window. The knob 290 is thenmoved to its rearmost position. as shown in Figure 9, and the subtrahendnumber is introduced by the hanger 1 is moved rearwardly, the pin 313 iswithin the upper trace slot- 311. Completion of the handle depression,which also moves the hanger 301, then turnsthe cam 260 in clockwisedirection and lowers the shaft 253. This lowers all of the totalizerbars so that their upper rack portions 255' engage the totalizerpinions. Thus upon lifting the handle 150 these rack bars which wereallowed to move rearwardly to extents controlled by the particular stoplugs depressed by the actuated number keys rotate the correspondingtotalizer wheels in directions to effect a subtracting action. Where anyofthese wheels moves between a O and "9 indication, the carry-overoperates as in efiecting addition, except in the subtraction because thereverse direction rack is in operative relation to the pinions.

Clearing It is, of course, necessary to bring all the totalizer wheels;to 0 before starting an addition operation. Means are provided by whichthis may be done by actuation of the handle bar 150. For this purposethe knob 290 is moved forwardly to its extreme position shown in Figure10. In this position of the parts the L-shaped' cam surface 354. at oneend of the notch and a shoulder 355 at its opposite end. Beyond theshoulder 355 is a cam face 357. Riding on the cam faces 354 and 357 arefollower rolls 358 andv 359, respectively, on a pair of scissorelements360 and 361, respectively. These scissor elements 360 and 361 each haveslots in their upper ends as at 362, each of which takes over a fixedpivot 363 projecting from the wall 217. These scissor elements are thuspermitted an up and down motion at the slots 362, fulcruming about thecenters of the cam follower rolls 358 and 359 and they also have pivotalmotion about the fixed pivot 363. The pivot pin 352,

located between adjacent edges of the scissor elements 360 and 361 whichare notched to receive it, acts to limit the swinging motion of eachscissors element toward the other. These scissor elements are movable inoverlying planes and at their lower ends they are provided withoppositely directed flanges 365 and 366 which project over into a commonplane and in the same plane with a lug 367 upstanding from an arm 368pivoted at 369 to the hanger 301. This arm 368 has a cam follower roll370 in position to be contacted by an inclined cam face 371 at therearward end of the right hand side member of the under-carriage. Thissame side member has an oppositely sloped cam face 372 spaced forwardlyof the cam face 371. When the knob 290 is in the clear position, theplate 351 is rocked to the position shown in Figure 10, the cam follower358 then riding at. the base of the elongated notch 353, while the camfollower roll 359 rides on the cam face 357. In this position of theparts, the lower end of the scissors member 360 is immediately above thelug 367 and prevents lifting the rear end of the arm 368 by engagementof the follower roll 370- on the cam face 371, beyond thelimited motionrequired to bring the bottom of the scissors slot against the pivot 363as shown in Figure 11. It is, however, lifted sufliciently to come abovethe lower end of the other scissors member 361. Continued rearwardmotion of the under-carriage, since the arm 368 cannot lift, causes thisarm, together with the hanger 301 to which it is attached, to moverearwardly with it and it also causes the other scissors member 361 toswing to the dotted line position shown in Figure 11. The movement ofthe hanger 301 rearwardly causes the trace to be 13 moved in the samemanner that it did during adding and thus rocks the cams 260counterclockwise and raises all the totalizer bars 250 to bring theirlower rack bars into engagement with the totalizer gears and it alsoretracts the totalizer wheel locks 140, but this after only a shortrearward travel of the under-carriage. The adjustment of the pivot 290to clear position also moves forwardly a slide plate 372 (Figures 3 and29) having a notch 373 engaging a pin 3730 on the arm 280, so that arear edge portion 374 thereof extends above a shoulder 245 on the dog235. This prevents the turning of this dog and holds the hooks 220elevated so that all the pilot bars are free to be moved rearwardly withthe under-carriage. Continued rearward travel of the carriage thereafterthus rotates all of the pinions until each is stopped by engagement ofone or the other of its totalizer wheel ears 135 with a stop 375 (seeFigures 5 and 13). This stop 375 is pivoted at 376 to the frame member217 and is provided with a downwardly extended slotted arm 377 whichengages over a pin 378 projecting from the inner face of the plate 351and which may form a pivotal connection to the link 350. When this plate351 was initially rocked by the positioning of the knob 290 in clearposition, the stop 3'75 was brought down into the dotted line positionshown in Figure 13 where it is in position to be engaged by thetotalizer wheel ears 135. The undercarriage may continue its full strokerearwardly while the bars 250 are stopped by the positive stopping oftheir respective totalizer wheels in any position in which they mayhappen to be, further motion of the under-carriage merely extending thesprings 206 which act independently for each of the pilot bars. When thelower ends of the scissors elements are sufliciently separated to permitthe lug 367 to move upwardly between them, the side member 175 is thenfreed for motion independently of the continued rearward motion of thehanger so that it can complete its rearward stroke until such time asthe cam follower 370 drops back of the cam face 372 of the side member175 into the position shown in Figure 12. The return motion of thehandle 150 causes the totalizer bars to be immediately brought out ofmesh with the totalizer pinions, the clearing action of the wheelshaving now been completed. The lowering of the lug 367 as the camfollower roll 371 rolls down the cam faces 372 permits the scissorsmember 361 to return to its former position close to the scissors member360 and with its lower end immediately above the lug 367. Thereafter asthe under-carriage is pulled forwardly by lifting the handle 150, sincethe lug 367 is now prevented from lifting beyond the lost motionpermitted at the pivot 363, the hanger 301 is immediately connected forretraction with the under-carriage which presses forwardly on the trace270 and rocks the cams 260 in clockwise direction, returning them to theoriginal position. Thus the return motion of the totalizer bars is outof operative contact with the totalizer pinions.

Means are provided for releasably locking the handle 290 in either itsclear or subtract positions. As shown on Figures 3 and 10, this meanscomprises a pair of arms 380 and 381 fixed to the cam pivot shaft 278.The arm 380 extends back of the arm 280 and is provided with a pair ofspaced shoulders 382 and 383, between which is a concave face 384. A lug385 on the arm 280 is adapted to be engaged with either of the shoulders383 or 382, or with the face 384. When the arm 280 is in its forwardposition at clear as shown in Figure 10, the lug 385 is in engagementwith the shoulder 383. The arm 381 has pivoted thereto adjacent to itsforward end, a dog 390 having a curved cam face 391 which may be engagedby a bevel face 392 on the hanger 301 when the hanger is movedtheretoward as in Figure 12. In this position of the parts, a lug 393 onthe dog engages a stop 394 on the arm 381, and the dog 390 is ordinarilyheld in this angular position as by a leaf spring 395. Since the dogcannot rock clockwise from the position shown in Figure 12, when theinclined face 392 of the hanger strikes it, the arm 381 is rockedupwardly, rocking the arm 380 and lifting it from engagement with thelug 385. This releases the arm 280 from clear position. When the arm 230is in subtract position, the shoulder 382 engages the lug 385 and here,again, as the hanger is retracted, the arm 380 is lifted, releasing thelock. When the hanger 301 is moved in the reverse direction, as from theposition shown in Figure 11 to that shown in Figure 12, the dog 390 mayyield and permit it to pass without lifting the locking arm 380. Thislocking arm can be released at any time, however, by the operator, bymerely depressing a pin 397 which extends through the casing, and thelower end of which bears on a rear ward extension 3598 of the arm 381.

When the arm 280 is in its intermediate add position or in subtractingposition, the plate 351 is in such angular relation that the scissorsmembers have their cam followers 358, 359 riding on their high points ofthe plate 351 which holds their lower ends separated in the positionsshown in Figure 3 so that they offer no obstruction to the lifting ofthe lug 367, so that the hanger is not coupled to move with theunder-carriage until toward the end of the under-carriage backwardstroke.

The selective stop carriage return mechanism As before noted, at the endof a number-selecting operation, at which time the selector stopcarriage 40 has been moved at least part way toward the left side of themachine, the upward motion of the handle normally returns the carriageto its starting position at the extreme right hand end of its travel.Such action occurs at the end of the normal adding or subtractingoperations, but certain variations of this are possible. The returnmechanism comprises a stop lever 400 (Figures 23 and 24) which ispivoted at 401 to the arm 58 between its ends and overlies the forwardextension of the under-carriage member 179. This stop lever 400 isprovided with a forwardly extending actuating and controlling arm 402 oneither side of which may be engaged downwardly extending forks 403 of acontrolling slide 404. This slide is movable along a guide post 405 andmay be yieldingly latched in any one of three axial positions as by aspring pressed ball latch 406 which engages in any selected of threeperipheral grooves 407, 408 and 409 of the post 405. An actuating piece410 which extends through a slot 411 in the forward wall of the casingengages with the slide 484 and may be employed to move the slide to anyselected of its three axial positions. The forward end of the lever 400has an end shoulder 412 which extends well forwardly, a second shoulder413 at a much shorter distance from the fulcrum 401 and between them ispositioned a slot 414. When the stop lever is in its mid-position shownin Figure 23, the flange of the under-carriage as it is moved backwardlyfinally contacts with the shoulder 413 and rocks the right hand end ofthe lever 58 forwardly to an amount sufficient to permit a latch 420pivotally carried by the guide pin 62 to be swung outwardly under theaction of a torsion spring 421 from the position shown in Figure 23 tothat shown in Figure 24 in which the end portion 421 of the latchengages a lug 422 on the sliding plate 55. On subsequent lifting of theoperating handle 150, which retracts the under-carriage, the cam roll onthe under-carriage engaging the lever 58, pushes the slide 55rearwardly, turning the segment 51 clockwise and winding the ribbon 50thereon, thus to return the carriage to its starting position shown inFigure 23. Just as it reaches this position, a fixed abutment 425 isengaged by a lug 426 projecting from the latch 420 so that the latch isrocked out of engagement with the lug 422, thus releasing the carriagefor lateral motion toward the left when this is 15 caused by depressionof one more of the number keys.

Should the operator discover that he has made an error in depressing anyof the number keys, he may wish to return the selector stops to neutralraised positions without imparting any motion to the totalizer wheels.When this is desired, the actuator 410 is moved to its left hand orerror position, bringing the shoulder 412 in line with the lug 191 ofthe under-carriage. On then actuating the handle bar 150 to a smallextent, the lever 58 starts its rearward rocking motion very early andthe lever 58 reaches its limit corresponding to Figwe 24 before thehandle 250 has been moved suflicient- 1y to displace the totalizeractuator bars. The operator then returns the handle bar 150 to itsupright position, whereupon the return of the under-carriage to itsstarting position returns the stop selector carriage to its startingposition and all of the selector stops which are then depressed arelifted by the lifter plate 47.

In some cases it may be desired torepeat the same sequence of digits forsuccessive totalizing operations. Insucha case it will not be desired toreturn the carriage between successive totalizer actions, but to producethese totalizer actions without disturbing the previous setting of theselector stops or the carriage position. When this is desired, thecontrol member 410 is moved to its right hand or repeat position, inwhich the lever 400' is swung to the right to the extreme dotted lineposition shown in Figure 24. In this position, backward motion of theunder-carriage by depression of the handle 150 causes the lug lever 190to ride into the slot 414 of the lever 400. This causes the motion ofthe handle 150 to fail to move this lever 400 so that the lever 58' isnot moved to the position of Figure 24. Thus when the operating handle150 is actuated, the carriage remains in its former position andrepeated actuations of the hand lever 150 will cause repeated additionsor subtractions of the same number for which the selective stops havebeen set, depending on whether adding or subtracting is being done,determined by the setting of the control knob 290.

Operation From the foregoing description of the machine, it will beunderstood that with the control knob 290 set at the add position, theoperator may depress the number keys in the order of the digits of thenumber to be added which will cause the selector carriage stops to beset accordingly, and the selector carriage to be moved to the left to anextent depending upon the number of keys depressed. The swinging down ofthe handle bar 150 by the operator, followed by a rise of this handle,will then cause the totalizer wheels to be rotated each by the amount ofthe number key depressed for that particular column of digits, and ateach return of the handle 150 the selector stop carriage will bereturned to its initial position ready for the next row of figures to beadded to the first. This next row is then introduced into the machine bypressing the number keys in the order that these digits appear from leftto right, and this number is then added to the preceding by a downwardand then upward motion of the handle 150, whereupon the machine is thenin condition to receive another set of digits of another number to beadded. This action takes place until the desired. amount of addition hasbeen accomplished, the total then appearing on the totalizer wheelsvisible through the sight opening.

After addition has been completed, the machine may be cleared byadjusting the knob 290 to its foremost position and then depressingandraising the handle bar 150. This will return all the totalizer wheelsto indication.

When it is desired to subtract, the minuend number is introduced intothe totalizer wheels by an adding operation, the digits of the numberbeing introduced by depressing the corresponding number keys and thenmanipulating the handle 150. The control knob 290 is then moved tosubtract in its rearward position, and the subtrahend is then introducedinto the machine by depressing the number keys in the order of thedigits of this ntunber. The handle is then given a downward stroke andreleased, whereupon the totalizer wheels will indicate the remainder.The machine may then be cleared in the same manner as before.

Means are provided by which a complete stroke of the operating handle150 is insured for each adding, subtracting, or clearing operation, ashort stroke being permitted only where an error has been committed andit is desired to erase a number introduced into the machine through theselector stops and before an addition or subtraction has been made. Thismeans is illustrated in Figure 6. The lower end of the arm may beprovided with a pivoted dog 430 normally held in the angular positionshown in full lines in Figure 6 as by a spring 431. This dog is adaptedto bemoved over the upper edge of a plate 432 which is provided with aplurality of serrations 433 at its intermediate portion and withunserrated arcuate end portions 434 and 435. The arm 170 may be swungfrom its forward position shown, rearwardly until the dog 430 approachesthe first apex 436 of the serrations and returned freely. The extent ofthis permissible motion is suiiicient to provide for return of the stopselector carriage erasing error in the depression of the number keys,but is insufficient to effect any motion of the totalizer bars effectiveto actuate the totalizer Wheels. However, after the arm 170 has beenswung beyond the first apex 436, the dog 430 will be swung into positionto obstruct return motion of the arm 170, as shown in the central dottedposition of Figure 6, so that the return motion cannot be initiateduntil the arm 170 has been moved beyond the last apex 437 of theserrated portion, whereupon the arm 170 is free to be returned to itsinitial position, the dog 430 swinging in the reverse directionsufficiently to clear the apices of the serrated portion.

The machine may be made so small and compact that it is convenient forthe operator to adjust the knob 290 and to depress the number keys withthe fingers of either hand and then to depress the actuator bar 150 bydownward and forward pressure of the heel of the same hand, the actuatorbar 150 returning to starting position as soon as pressure from theoperators hand is released. Thus the use of only one hand is necessaryto operate the machine, the other hand being free for other use.

From the foregoing description of an embodiment of this invention itwill be evident to those skilled in the art that various changes andmodifications may be made without departing from its spirit or scope.

Having thus described my invention, what is claimed as new and desiredto be secured by Letters Patent is:

A computing machine comprising a totalizer, actuator racks operativelyassociated with said totalizer, longitudinally movable difierentialmembers resiliently connected to said actuator racks, a reciprocativeunder-carriage yieldingly connected to said differential members fordriving said members and their associated actuator racks, a manuallyoperable drive member, resilient means connecting said drive member andsaid under-carriage, said under-carriage having associated therewithmeans limiting its speed of operation comprising a Weight, meanssupporting said weight for oscillatory motion, and means actuated bysaid under-carriage for oscillating said weight and thereby producingvibration of said machine which tends to avoid sticking of relativelymovable parts.

References Cited in the file of this patent UNITED STATES PATENTS876,232 Pike Jan. 7, 1908 904,561 Pike Nov. 24, 1908 1,001,688 RinscheAug. 29, 1911 1,016,287 Perkins Feb. 6, 1912 1,872,439 Friden Aug. 16,1932

